The 2day/1night option with ability to change the return date seems good.

Unfortunately, the website does not seem to give the option to change the return date, atleast until the point it asks for the credit card information. Does it allow to change the date, after I put in the credit card information?

I also called them on the phone. The lady said that they do not allow to change the return date when booking for two day/one night, but will allow to change the return date if booking for two or more nights. Well that is what I understood...

Any suggestions?